Can't fit 32t cassette on Croix de Fer?

pangolin

I got a new cassette, tiagra 32t. I also got a 105 5701 GS mech as I understood this was large enough for 32t and compatible with tiagra 4600 shifters. But it just bangs into the 32t cog once on the bike.

What am I missing? It's a 2014 croix de fer if that makes a difference?

pangolin

veronese68

You need to screw in the b screw, it is the screw that points forward and pushes against the gear hanger rotating the derailleur down and away from the big sprocket. Should be shown in the instructions that came with the mech.

pangolin

I tried the b screw. Then realised the derailleur doesnt fully extend unless there's a chain on it putting tension on the cogs. Fits fine, what a tit. Cheers veronese68!

veronese68

That's obvious now you say it. :-) The joy of hindsight.